Methods, systems, and computer readable media for enabling forwarding of subsequent network function subscription updates

ABSTRACT

Methods, systems, and computer readable media for enabling forwarding of subsequent network function subscription updates. A method includes forwarding, from a bootstrapped network function repository function (NRF) in a first region, a subscription creation request from a consumer network function to a target NRF in a second region. The method includes creating, at the target NRF, a subscription for the consumer network function. The method includes generating, at the target NRF, a hint comprising data indicating one or more alternate NRFs each sharing subscription state data with the target NRF. The method includes sending, from the target NRF to the consumer network function, a subscription response message including the hint.

TECHNICAL FIELD

The subject matter described herein relates to telecommunicationsnetworks. More particularly, the subject matter described herein relatesto methods, systems, and computer readable media for enabling forwardingof subsequent network function subscription updates.

BACKGROUND

In fifth generation (5G) communications networks, the network node thatprovides service is referred to as a producer network function (NF). Anetwork node that consumes services is referred to as a consumer NF. Anetwork function can be both a producer NF and a consumer NF dependingon whether it is consuming or providing service.

A given producer NF may have many service endpoints, where a serviceendpoint is the point of contact for one or more NF instances hosted bythe producer NF. The service endpoint is identified by a combination ofInternet protocol (IP) address and port number or a fully qualifieddomain name that resolves to an IP address and port number on a networknode that hosts a producer NF. An NF instance is an instance of aproducer NF that provides a service. A given producer NF may includemore than one NF instance. It should also be noted that multiple NFinstances can share the same service endpoint.

Producer NFs register with a network function repository function (NRF).The NRF maintains service profiles of available NF instances identifyingthe services supported by each NF instance. Consumer NFs can subscribeto receive information about producer NF instances that have registeredwith the NRF.

Consumer NFs can send subscription requests to NRFs. NRFs can forwardsubscription requests to other NRFs. For example, within a public landmobile network (PLMN), a NRF in one region of the PLMN may forward asubscription request another NRF in a different region of the PLMN.NRFs, however, may sometimes need to be able to determine an appropriateNRF for forwarding subsequent network function subscription updates.

In light of these and other difficulties, there exists a need formethods, systems, and computer readable media for enabling forwarding ofsubsequent network function subscription updates.

SUMMARY

Methods, systems, and computer readable media for enabling forwarding ofsubsequent network function subscription updates. A method includesforwarding, from a bootstrapped network function repository function(NRF) in a first region, a subscription creation request from a consumernetwork function to a target NRF in a second region. The method includescreating, at the target NRF, a subscription for the consumer networkfunction. The method includes generating, at the target NRF, a hintcomprising data indicating one or more alternate NRFs each sharingsubscription state data with the target NRF. The method includessending, from the target NRF to the consumer network function, asubscription response message including the hint.

According to another aspect of the subject matter described herein, thehint is included with or appended to a subscription identifier.

According to another aspect of the subject matter described herein, thehint comprises a region identifier for the second region.

According to another aspect of the subject matter described herein, themethod includes receiving, at the bootstrapped NRF, a retry attempt fromthe consumer network function resulting from the target NRF notresponding to the consumer network function, the retry attempt includingthe hint.

According to another aspect of the subject matter described herein, themethod includes, at the bootstrapped NRF, using the hint to forward theretry attempt to a first alternate NRF of the one or more alternate NRFssharing subscription state data with the target NRF.

According to another aspect of the subject matter described herein, themethod includes, at the first alternate NRF, creating a new subscriptionfor the consumer network function and sending a new subscriptionresponse message to the consumer network function.

According to another aspect of the subject matter described herein,generating the hint comprises generating the hint in conjunction withcreating a subscription ID and processing the subscription creationrequest.

According to another aspect of the subject matter described herein,generating the hint comprises inserting the hint into a createdsubscription ID while sending the subscription response message.

According to another aspect of the subject matter described herein, theconsumer network function is configured with a list of NRFs in the firstregion in a priority order.

According to another aspect of the subject matter described herein, thebootstrapped NRF is configured with a prioritized list of NRFs in thesecond region.

According to another aspect of the subject matter described herein, asystem for enabling forwarding of subsequent network functionsubscription updates includes a bootstrapped network function repositoryfunction (NRF) in a first region and a target NRF in a second region.The bootstrapped NRF is implemented by at least a first processor andconfigured for forwarding a subscription creation request from aconsumer network function to the target NRF. The target NRF isimplemented by at least a second processor and configured for: creatinga subscription for the consumer network function; generating a hintcomprising data indicating one or more alternate NRFs each sharingsubscription state data with the target NRF; and sending, to theconsumer network function, a subscription response message including thehint.

According to another aspect of the subject matter described herein, thehint is included with or appended to a subscription identifier.

According to another aspect of the subject matter described herein, thehint comprises a region identifier for the second region.

According to another aspect of the subject matter described herein, thebootstrapped NRF is configured for receiving a retry attempt from theconsumer network function resulting from the target NRF not respondingto the consumer network function, the retry attempt including the hint.

According to another aspect of the subject matter described herein, thebootstrapped NRF is configured for using the hint to forward the retryattempt to a first alternate NRF of the one or more alternate NRFssharing subscription state data with the target NRF.

According to another aspect of the subject matter described herein, thefirst alternate NRF is configured for creating a new subscription forthe consumer network function and sending a new subscription responsemessage to the consumer network function.

According to another aspect of the subject matter described herein,generating the hint comprises generating the hint in conjunction withcreating a subscription ID and processing the subscription creationrequest.

According to another aspect of the subject matter described herein,generating the hint comprises inserting the hint into a createdsubscription ID while sending the subscription response message.

According to another aspect of the subject matter described herein, theconsumer network function is configured with a list of NRFs in the firstregion in a priority order.

According to another aspect of the subject matter described herein, thebootstrapped NRF is configured with a prioritized list of NRFs in thesecond region.

According to another aspect of the subject matter described herein, oneor more non-transitory computer readable media have stored thereonexecutable instructions that when executed by at least one processor ofa computer cause the computer to perform steps comprising forwarding,from a bootstrapped network function repository function (NRF) in afirst region, a subscription creation request from a consumer networkfunction to a target NRF in a second region; creating, at the targetNRF, a subscription for the consumer network function; generating, atthe target NRF, a hint comprising data indicating one or more alternateNRFs each sharing subscription state data with the target NRF; andsending, from the target NRF to the consumer network function, asubscription response message including the hint.

The subject matter described herein can be implemented in software incombination with hardware and/or firmware. For example, the subjectmatter described herein can be implemented in software executed by aprocessor. In one example implementation, the subject matter describedherein may be implemented using a computer readable medium having storedthereon computer executable instructions that when executed by theprocessor of a computer control the computer to perform steps.

Example computer readable media suitable for implementing the subjectmatter described herein include non-transitory devices, such as diskmemory devices, chip memory devices, programmable logic devices, andapplication specific integrated circuits. In addition, a computerreadable medium that implements the subject matter described herein maybe located on a single device or computing platform or may bedistributed across multiple devices or computing platforms.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter described herein will now be explained with referenceto the accompanying drawings of which:

FIG. 1 is a block diagram illustrating an example 5G system networkarchitecture;

FIG. 2 is a block diagram of an example PLMN that illustrates NRF-NRFinterconnection;

FIG. 3 is a message flow diagram illustrating an example within-PLMNnetwork function subscription creation flow;

FIG. 4 is a message flow diagram illustrating a failed subsequentsubscription update;

FIG. 5 is a message flow diagram illustrating enabling forwarding ofsubsequent network function subscription updates;

FIG. 6 is a message flow diagram illustrating forwarding of subsequentnetwork function subscription updates using the hint;

FIG. 7 is a message flow diagram illustrating forwarding of subsequentnetwork function subscription updates when initial re-routing fails;

FIG. 8 is a flow diagram of an example method for enabling forwarding ofsubsequent network function subscription updates.

DETAILED DESCRIPTION

The subject matter described herein relates to methods, systems, andcomputer readable media for enabling forwarding of subsequent networkfunction subscription updates.

The NRF is the network entity in the 5G core network (5GC) supportingthe following functionality:

-   -   Maintains the NF profiles of available NF instances and their        supported services;    -   Maintains the service communication proxy (SCP) profiles of        available SCP instances;    -   Allows other NF or SCP instances to subscribe to and be notified        of the registration in the NRF of new NF instances of a given        type. It also allows SCP instances to subscribe to and be        notified of the registration in the NRF of new SCP instances;    -   Supports the service discovery function. The NRF receives NF        discovery requests from NF or SCP instances and provides the        information of the available NF instances fulfilling certain        criteria (e.g., supporting a given service);    -   Supports the SCP discovery function. It receives NF discovery        requests for SCP profiles from other SCP instances and provides        the information of the available SCP instances fulfilling        certain criteria (e.g., serving a given NF set).

The methods, systems, and computer readable media described in thisdocument can be implemented in the NRF. In some examples, a method forenabling forwarding of subsequent network function subscription updatesincludes creating a “hint” in or with the subscription identifiergenerated for forwarded within-PLMN network function subscriptioncreation requests by the NRF. The hint can be used for forwardingsubsequent network function subscription update and delete requests forthe same subscription to the same or equivalent NRFs sharing state databy initial or intermediate NRFs.

FIG. 1 is a block diagram illustrating an example 5G system networkarchitecture. The architecture in FIG. 1 includes NRF 100 and SCP 101,which may be located in the same home public land mobile network(HPLMN). NRF 100 may maintain profiles of available producer NF serviceinstances and their supported services and allow consumer NFs or SCPs tosubscribe to and be notified of the registration of new/updated producerNF service instances.

-   -   SCP 101 may also support service discovery and selection of        producer NF instances. SCP 101 may perform load balancing of        connections between consumer and producer NFs. In addition,        using the methodologies described herein, SCP 101 may perform        preferred NF location based selection and routing.

NRF 100 is a repository for NF or service profiles of producer NFinstances. In order to communicate with a producer NF instance, aconsumer NF or an SCP must obtain the NF or service profile or theproducer NF instance from NRF 100. The NF or service profile can be aJavaScript object notation (JSON) data structure as defined in 3GPPTechnical Specification (TS) 29.510.

In FIG. 1 , any of the nodes (other than NRF 100) can be either consumerNFs or producer NFs, depending on whether they are requesting orproviding services. In the illustrated example, the nodes include apolicy control function (PCF) 102 that performs policy relatedoperations in a network, a user data management (UDM) function 104 thatmanages user data, and an application function (AF) 106 that providesapplication services.

The nodes illustrated in FIG. 1 further include a session managementfunction (SMF) 108 that manages sessions between access and mobilitymanagement function (AMF) 110 and PCF 102. AMF 110 performs mobilitymanagement operations similar to those performed by a mobilitymanagement entity (MME) in 4G networks. An authentication serverfunction (AUSF) 112 performs authentication services for user equipment(UEs), such as user equipment (UE) 114, seeking access to the network.

A network slice selection function (NSSF) 116 provides network slicingservices for devices seeking to access specific network capabilities andcharacteristics associated with a network slice. A network exposurefunction (NEF) 118 provides application programming interfaces (APIs)for application functions seeking to obtain information about Internetof things (IoT) devices and other UEs attached to the network. NEF 118performs similar functions to the service capability exposure function(SCEF) in 4G networks.

A radio access network (RAN) 120 connects user equipment (UE) 114 to thenetwork via a wireless link. Radio access network 120 may be accessedusing a g-Node B (gNB) (not shown in FIG. 1 ) or other wireless accesspoint. A user plane function (UPF) 122 can support various proxyfunctionality for user plane services. One example of such proxyfunctionality is multipath transmission control protocol (MPTCP) proxyfunctionality.

UPF 122 may also support performance measurement functionality, whichmay be used by UE 114 to obtain network performance measurements. Alsoillustrated in FIG. 1 is a data network (DN) 124 through which UEsaccess data network services, such as Internet services.

SEPP 126 filters incoming traffic from another PLMN and performstopology hiding for traffic exiting the home PLMN. SEPP 126 maycommunicate with an SEPP in a visitor PLMN which manages security forthe visitor PLMN. Thus, traffic between NFs in different PLMNs maytraverse two SEPP functions, one for the home PLMN and the other for thevisitor PLMN.

The service operations defined for NRF 100 can include one or more ofthe following, as defined in Third Generation Partnership Project (3GPP)Technical Specification (TS) 29.510:

-   -   NFRegister: The NFRegister service operation allows an NF or SCP        instance to register its profile in the NRF. The NFRegister        service operation includes the registration of the general        parameters of the NF or SCP instance, together with the list of        potential services exposed by the NF or SCP instance. This        service operation is not allowed to be invoked from an NRF in a        different PLMN.    -   NFUpdate: The NFUpdate service operation allows an NF or SCP        instance to replace or update partially the parameters of its        profile (including the parameters of the associated services, if        any) in the NRF. The NFUpdate service operation also allows an        NF instance to add or delete individual services offered by the        NF instance. This service operation is not allowed to be invoked        from an NRF in a different PLMN.    -   NFDeregister: The NFDeregister service operation allows an NF or        SCP instance to deregister its profile in the NRF, including the        services offered by the NF Instance, if any. This service        operation is not allowed to be invoked from an NRF in a        different PLMN.    -   NFStatusSubscribe: The NFStatusSubscribe service operation        allows an NF or SCP instance to subscribe to changes on the        status of NF instances registered in NRF. The NFStatusSubscribe        service operation also allows an SCP Instance to subscribe to        changes on the status of other SCP Instances registered in the        NRF. This service operation can be invoked by an NF instance in        a different PLMN (via the local NRF in that PLMN). The        NFStatusSubscribe service operation cannot be invoked by an SCP        instance in a different PLMN.    -   NFStatusNotify: The NFStatusNotify service operation allows the        NRF to notify subscribed NF or SCP instances of changes on the        status of NF Instances. The NFStatusNotify service operation        also allows the NRF to notify subscribed SCP instances of        changes in status of SCP instances. This service operation can        be invoked directly between the NRF and an NF instance in a        different PLMN (without involvement of the local NRF in that        PLMN). The StatusNotify service operation cannot be invoked        between the NRF and an SCP instance in a different PLMN.    -   NFStatusUnsubscribe: The NFStatusUnsubscribe service operation        allows an NF or SCP Instance to unsubscribe to changes on the        status of NF Instances registered in the NRF. The        NFStatusUnsubscribe service operation also allows an SCP        instance to unsubscribe to changes on the status of other SCP        instances registered in NRF. This service operation can be        invoked by an NF instance in a different PLMN (via the local NRF        in that PLMN). It cannot be invoked by an SCP instance in a        different PLMN.    -   NFListRetrieval: The NFListRetrieval service operation allows        retrieving a list of NFs and SCPs currently registered in the        NRF. This service operation is not allowed to be invoked from an        NRF in a different PLMN.    -   NFProfileRetrieval: The NFProfileRetrieval service operation        allows retrieving the profile of a given NF or SCP instance.        This service operation is not allowed to be invoked from an NRF        in a different PLMN.

NRF 100 can offer a bootstrapping service to let consumer networkfunctions of NRF 100 know about the service endpoints it supports, byusing a version-independent URI endpoint that does not need to bediscovered by using a discovery service. The version independent URI canidentify, e.g., NRF 100 or the producer NFs registered with NRF 100.

This service can be used in inter-PLMN scenarios where the NRF in aPLMN-A needs to invoke services from an NRF in PLMN-B, when there is nopre-configured information indicating the version of the servicesdeployed in PLMN-B. This service may also be used in intra-PLMNscenarios to avoid configuring statically in the different NFsinformation about the service versions deployed in the NRF to be used bythose NFs.

Consumer NFs can send subscription requests to NRF 100. NRF 100 canforward subscription requests to other NRFs. For example, within apublic land mobile network (PLMN), a NRF in one region of the PLMN mayforward a subscription request another NRF in a different region of thePLMN.

NRF 100 can be configured to include a “hint” in or with thesubscription identifier generated for forwarded within-PLMN networkfunction subscription creation requests. The hint can be used forforwarding subsequent network function subscription update and deleterequests for the same subscription to the same or equivalent NRFssharing state data by initial or intermediate NRFs.

In some examples, one or more NRFs, such as NRF 100, perform a methodthat includes forwarding, from a bootstrapped NRF in a first region, asubscription creation request from a consumer network function to atarget NRF in a second region. The method includes creating, at thetarget NRF, a subscription for the consumer network function. The term“bootrapped NRF” refers to an NRF that is configured with a prioritizedlist of NRFs in another region that the NRF contacts in a priority orderto obtain NF profiles of producer NFs in another region.

The method includes generating, at the target NRF, a hint comprisingdata indicating one or more alternate NRFs each sharing subscriptionstate data with the target NRF. The method includes sending, from thetarget NRF to the consumer network function, a subscription responsemessage including the hint.

FIG. 2 is a block diagram of an example PLMN 200 that illustratesNRF-NRF interconnection. PLMN 200 includes more than one region; forpurposes of illustration, three example regions are shown. Requestforwarding may span two or more regions. FIG. 2 shows an example NRF-NRFforwarding use-case such that PLMN 200 includes region 202, region 204,and region 206.

A consumer network function 208 in region 202 is configured, e.g., byvirtue of a stored list of identifiers or addresses, to access NRFs inregion 202 to serve in a priority order in case of NRF failure in region202. For example, the priority order may specify consumer networkfunction 208 to access NRF 210 first, and if NRF 210 is not available,to then access NRF 212. If NRF 212 is not available, consumer networkfunction 208 then attempts to access NRF 214, and so on.

Each of NRFs 210, 212, and 214 in region 202 is configured, e.g., byvirtue of a stored list of identifiers or addresses, to access NRFs inremote regions to serve in a priority order in case of NRF forwarding toNRFs in other regions. For example, FIG. 2 illustrates priority ordersfor NRF 210.

NRF 210, when forwarding requests to region 204, will first attempt toforward a request to NRF 216 in region 204. If NRF 216 is unavailable,then NRF 210 will attempt to forward the request to NRF 218 in region204. If NRF 218 is unavailable, then NRF 210 will attempt to forward therequest to NRF 220 in region 204, and so on.

Similarly, NRF 210, when forwarding requests to region 206, will firstattempt to forward a request to NRF 222 in region 206. If NRF 222 isunavailable, then NRF 210 will attempt to forward the request to NRF 224in region 206. If NRF 224 is unavailable, then NRF 210 will attempt toforward the request to NRF 226 in region 206, and so on.

FIG. 3 is a message flow diagram illustrating an example within-PLMNnetwork function subscription creation flow 300. FIG. 3 shows the threeregions 202, 204, and 206 from FIG. 2 . FIG. 3 shows the consumernetwork function 208 and NRF 210 in region 202, NRF 216 in region 204,and NRFs 222 and 224 in region 206.

Consumer network functions can be bootstrapped/configured with lists ofNRFs (in a priority order) serving consumer network functionslocalities. Consumer network functions communicate with NRFs forNRF-specific operations, for example, network function registrations,updates, de-registrations, subscription creations, and discovery andaccess-tokens.

Based on subscription request parameters, a bootstrapped NRF may processa subscription request locally or may forward the subscription requestto an NRF in another region. An NRF, in response to receiving aforwarded network function subscription creation request, validateswhether it can create the subscription or whether it should determine toforward the request to an NRF in another region.

In the example shown in FIG. 3 , consumer network function 208 sends anew subscription request 302 to NRF 210. Consumer network function 208is configured to select NRF 210 as a priority NRF, i.e., such that NRF210 is the bootstrapped NRF for consumer network function 208.

NRF 210 forwards the subscription request 304 to NRF 216 in region 204based on forwarding criteria. NRF 216 determines to forward thesubscription request 306 again based on forwarding criteria. NRF 216forwards the subscription request 306 to NRF 222 in region 206.

At 310, NRF 222 creates the subscription and creates a subscriptionidentifier for the subscription. NRF 222 sends a subscription response312 all the way back to consumer network function 208 in the reversedirection of the request. The subscription response 312 includes thesubscription identifier. The subscription response 312 can also includethe resource path of the subscription in a location header, e.g.,including the NRF forwarding chain.

FIG. 4 is a message flow diagram illustrating a failed subsequentsubscription update 400. FIG. 4 shows the three regions 202, 204, and206 from FIG. 2 . FIG. 4 shows the consumer network function 208 and NRF210 in region 202, NRF 216 in region 204, and NRFs 222 and 224 in region206.

As per 3GPP TS 29.510, consumer network function 208 is expected to sendthe subscription update/delete requests directly to the NRF as specifiedin the subscription resource received in the location header whilecreating the subscription, i.e., to NRF 222. Nonetheless, there is apossibility that when the target NRF, NRF 222, specified in the locationheader is unavailable/down, the subscription update/delete request willfail.

As shown in FIG. 4 , consumer network function attempts to send asubscription update 402 directly to the NRF identified in the locationheader received in the subscription creation request, i.e., to NRF 222.NRF 222, however, is crashed or unreachable at 404 in this example.

Now, considering that region 206 may have alternate NRFs sharing statedata with the failed target NRF, NRF 222, that can serve the subsequentnetwork function subscription updates/delete requests, consumer networkfunction 208 in region 202 could possibly be configured to attempt tosend the subscription update to the alternative NRFs in region 206.

It may be challenging, however, if the onus of retrying to alternativeNRFs in region 206 lies with consumer network function 208. Such aconfiguration could present the following challenges at consumer-NFs:

-   -   Every consumer NF needs to be provisioned with details of        alternative NRFs in all regions.    -   Every consumer NF needs to implement retry logic.

These technical challenges could be a hassle to a telecommunicationsnetwork operator or to a consumer network function designer.

FIG. 5 is a message flow diagram illustrating enabling forwarding ofsubsequent network function subscription updates 500. FIG. 5 shows thethree regions 202, 204, and 206 from FIG. 2 . FIG. 5 shows the consumernetwork function 208 and NRF 210 in region 202, NRF 216 in region 204,and NRFs 222 and 224 in region 206.

The target NRF, NRF 222, can be configured to add a “hint” to thesubscription-Id included in the network function subscription creationresponse that identifies the target NRF, NRF 222, and all otherequivalent NRFs that share state data with the target NRF (in thisexample, NRF 224 and NRF 226). The hint is data specifying the alternateNRFs, and the hint can be comprised of any appropriate data andformatted as appropriate for the system.

-   -   Equivalent NRFs share each other's state data to take up their        traffic, often seamlessly, when one or more of them fail.    -   The hint that is contained in/with the subscription-Id may be        added either:        -   when generating the subscription-Id (i.e. at the time of            processing NF subscription creation request), or        -   inserted in the generated subscription-Id when returning the            subscription creation response.

In either case, NRFs in regions 202, 204, and 206 can be configured toidentify the hint in subscription-Id to determine the target NRFsmaintaining this subscription.

As shown in FIG. 5 , consumer network function 208 sends a newsubscription request 502 to the bootstrapped NRF, NRF 210. NRF 210forwards the subscription request 504 to NRF 216 in region 204 based onforwarding criteria. For example, NRF 210 may determine that it lackssufficient information to fulfill subscription request 502. NRF 216 inregion 204 forwards the subscription request 506 to NRF 222 in region206 based on forwarding criteria.

NRF 222 create the subscription with the subscription-Id containing thehint of the NRFs that may equivalently serve the subscription. Forexample, NRF 222 may append a region identifier for the region of NRF222, region 206, to the subscription-Id. NRF 222 sends the subscriptionresponse 510 all the way back on the request flow to consumer networkfunction 208. The subscription response 510 includes thesubscription-Id, the hint, and the location header as described abovewith reference to FIG. 3 .

FIG. 6 is a message flow diagram illustrating forwarding of subsequentnetwork function subscription updates using the hint 600. FIG. 6 showsthe three regions 202, 204, and 206 from FIG. 2 . FIG. 6 shows theconsumer network function 208 and NRF 210 in region 202, NRF 216 inregion 204, and NRFs 222 and 224 in region 206.

When a network function subscription update/delete request attempted atthe subscription resource URI (i.e., received in location header inresponse to NF subscription create request) have failed due to thetarget NRF specified in the location header being down, the consumernetwork function shall re-attempt these network function subscriptionupdate/delete requests to the bootstrapped NRF. The following operationsmay be performed by the bootstrapped NRF and the target NRF.

-   -   The bootstrapped NRF may read the hint in the subscription-Id        from the request and identify the NRFs that can serve the        request.    -   Based on the NRFs identified, the bootstrapped NRF will forward        the NF subscription Update/Delete request in the order of        priorities provisioned in it, e.g., by the operator    -   The target NRF can then process the NF subscription/delete        request and send the response that will go back in the reverse        order of request.

As shown in FIG. 6 , consumer network function 208 sends a subscriptionupdate 602 directly to the NRF specified in the location header receivedfrom the subscription creation request, NRF 222. At 604, however, NRF222 is down.

Consumer network function 208 attempts to retry the subscription update606 at the bootstrapped NRF, NRF 210. NRF 210 identifies the targetregion, region 206, from the hint with/within the subscription-Id andattempts the subscription update with NRFs in region 206 in theprovisioned priority order. Since NRF 222 is down, NRF 210 forwards thesubscription request 608 to NRF 224 in region 206.

NRF 224, at 610, successfully processes the network functionsubscription update/delete operation. NRF 224 sends a response 612 backto consumer network function 208 in the reverse order of the request.

FIG. 7 is a message flow diagram illustrating forwarding of subsequentnetwork function subscription updates when initial re-routing fails 700.FIG. 7 shows two of the three regions from FIG. 2 , region 202 andregion 206. FIG. 7 shows the consumer network function 208, NRF 210, andNRF 212 in region 202; and NRFs 222 and 224 in region 206.

If re-routing fails to the first bootstrapped NRF, NRF 210, then thenext priority bootstrapped NRF can be retried by consumer networkfunction 208.

As shown in FIG. 7 , consumer network function 208 sends a subscriptionupdate 702 directly to the NRF specified in the location header receivedfrom the subscription creation request, NRF 222. At 704, however, NRF222 is down.

Consumer network function 208 attempts to retry the subscription update706 at the bootstrapped NRF, NRF 210. At 708, however, NRF 210 is down.

Consumer network function 208 attempts to retry the subscription update710 at NRF 212 in region 202 because NRF 212 is next in the priorityorder. NRF 212 identifies the target region, region 206, from the hintwith/within the subscription-Id and attempts the subscription updatewith NRFs in region 206 in the provisioned priority order.

Since NRF 222 is down, NRF 212 forwards the subscription request 712 toNRF 224 in region 206. NRF 224, at 714, successfully processes thenetwork function subscription update/delete operation. NRF 224 sends aresponse 716 back to consumer network function 208 in the reverse orderof the request.

FIG. 8 is a flow diagram of an example method 800 for enablingforwarding of subsequent network function subscription updates. Method800 is performed by a number of NRFs, such as the NRF 100 from FIG. 1 .

In general, method 800 includes providing a “hint” in or with thesubscription identifier generated for forwarded within-PLMN networkfunction subscription creation requests by the NRF. The hint can be usedfor forwarding subsequent network function subscription update anddelete requests for the same subscription to the same or equivalent NRFssharing state data by initial or intermediate NRFs.

Method 800 includes forwarding, from a bootstrapped network functionrepository function (NRF) in a first region, a subscription creationrequest from a consumer network function to a target NRF in a secondregion (802). The consumer network function can be configured with alist of NRFs in the first region in a priority order. The bootstrappedNRF can be configured with a prioritized list of NRFs in the secondregion.

Method 800 includes creating, at the target NRF, a subscription for theconsumer network function (804). Method 800 includes generating, at thetarget NRF, a hint comprising data indicating one or more alternate NRFseach sharing subscription state data with the target NRF (806). The hintcan be included with or appended to a subscription identifier. The hintcan include a region identifier for the second region.

The hint can be generated in conjunction with creating a subscription IDand processing the subscription creation request. Generating the hintcan include inserting the hint into a created subscription ID whilesending the subscription response message.

Method 800 includes sending, from the target NRF to the consumer networkfunction, a subscription response message including the hint (808).

In some examples, method 800 includes receiving, at the bootstrappedNRF, a retry attempt from the consumer network function resulting fromthe target NRF not responding to the consumer network function, theretry attempt including the hint. Method 800 can include, at thebootstrapped NRF, using the hint to forward the retry attempt to a firstalternate NRF of the one or more alternate NRFs sharing subscriptionstate data with the target NRF. Method 800 can include, at the firstalternate NRF, creating a new subscription for the consumer networkfunction and sending a new subscription response message to the consumernetwork function.

On advantage of the subject matter described herein is that thebootstrapped NRF can use the hint to route retries of a subscriptionupdate or delete request to an alternate NRF when a first deliveryattempt to the initial target NRF fails. Providing this functionality inthe NRF reduces the need for consumer NFs to be provisioned withalternate NRFs in other regions.

References

The disclosure of each of the following references is incorporatedherein by reference in its entirety.

1. 3rd Generation Partnership Project; Technical Specification GroupCore

Network and Terminals; 5G System; Network Function Repository Services;Stage 3 (Release 17) 3GPP TS 29.510 V17.3.0 (2021-09)

The scope of the present disclosure includes any feature or combinationof features disclosed in this specification (either explicitly orimplicitly), or any generalization of features disclosed, whether or notsuch features or generalizations mitigate any or all of the problemsdescribed in this specification. Accordingly, new claims may beformulated during prosecution of this application (or an applicationclaiming priority to this application) to any such combination offeatures.

In particular, with reference to the appended claims, features fromdependent claims may be combined with those of the independent claimsand features from respective independent claims may be combined in anyappropriate manner and not merely in the specific combinationsenumerated in the appended claims.

What is claimed is:
 1. A method for enabling forwarding of subsequentnetwork function subscription updates, the method comprising:forwarding, from a bootstrapped network function repository function(NRF) in a first region, a subscription creation request from a consumernetwork function to a target NRF in a second region; creating, at thetarget NRF, a subscription for the consumer network function;generating, at the target NRF, a hint comprising data indicating one ormore alternate NRFs each sharing subscription state data with the targetNRF; and sending, from the target NRF to the consumer network function,a subscription response message including the hint.
 2. The method ofclaim 1, wherein the hint is included with or appended to a subscriptionidentifier.
 3. The method of claim 1, wherein the hint comprises aregion identifier for the second region.
 4. The method of claim 1,comprising receiving, at the bootstrapped NRF, a retry attempt from theconsumer network function resulting from the target NRF not respondingto the consumer network function, the retry attempt including the hint.5. The method of claim 4, comprising, at the bootstrapped NRF, using thehint to forward the retry attempt to a first alternate NRF of the one ormore alternate NRFs sharing subscription state data with the target NRF.6. The method of claim 5, comprising, at the first alternate NRF,creating a new subscription for the consumer network function andsending a new subscription response message to the consumer networkfunction.
 7. The method of claim 1, wherein generating the hintcomprises generating the hint in conjunction with creating asubscription ID and processing the subscription creation request.
 8. Themethod of claim 1, wherein generating the hint comprises inserting thehint into a created subscription ID while sending the subscriptionresponse message.
 9. The method of claim 1, wherein the consumer networkfunction is configured with a list of NRFs in the first region in apriority order.
 10. The method of claim 1, wherein the bootstrapped NRFis configured with a prioritized list of NRFs in the second region. 11.A system for enabling forwarding of subsequent network functionsubscription updates, the system comprising: a bootstrapped networkfunction repository function (NRF) in a first region; and a target NRFin a second region; wherein the bootstrapped NRF is implemented by atleast a first processor and configured for forwarding a subscriptioncreation request from a consumer network function to the target NRF; andwherein the target NRF is implemented by at least a second processor andconfigured for: creating a subscription for the consumer networkfunction; generating a hint comprising data indicating one or morealternate NRFs each sharing subscription state data with the target NRF;and sending, to the consumer network function, a subscription responsemessage including the hint.
 12. The system of claim 11, wherein the hintis included with or appended to a subscription identifier.
 13. Thesystem of claim 11, wherein the hint comprises a region identifier forthe second region.
 14. The system of claim 11, wherein the bootstrappedNRF is configured for receiving a retry attempt from the consumernetwork function resulting from the target NRF not responding to theconsumer network function, the retry attempt including the hint.
 15. Thesystem of claim 14, wherein the bootstrapped NRF is configured for usingthe hint to forward the retry attempt to a first alternate NRF of theone or more alternate NRFs sharing subscription state data with thetarget NRF.
 16. The system of claim 11, wherein generating the hintcomprises generating the hint in conjunction with creating asubscription ID and processing the subscription creation request. 17.The system of claim 11, wherein generating the hint comprises insertingthe hint into a created subscription ID while sending the subscriptionresponse message.
 18. The system of claim 11, wherein the consumernetwork function is configured with a list of NRFs in the first regionin a priority order.
 19. The system of claim 11, wherein thebootstrapped NRF is configured with a prioritized list of NRFs in thesecond region.
 20. One or more non-transitory computer readable mediahaving stored thereon executable instructions that when executed by atleast one processor of a computer cause the computer to perform stepscomprising: forwarding, from a bootstrapped network function repositoryfunction (NRF) in a first region, a subscription creation request from aconsumer network function to a target NRF in a second region; creating,at the target NRF, a subscription for the consumer network function;generating, at the target NRF, a hint comprising data indicating one ormore alternate NRFs each sharing subscription state data with the targetNRF; and sending, from the target NRF to the consumer network function,a subscription response message including the hint.